Miller’s quick ear caught the sound.
“Hark!” he cried, starting up. “What’s that?”
“A mouse,” exclaimed the doctor, laughing. “I heard it. Don’t worry yourself, my dear James, we are safe enough now with that guard out of the way.”
By the aid of the candles they examined every floorboard, trying each to see if it were movable. But they were all fast, and gave no sign of covering any place of concealment. They seemed to be in search of some cavity where something they believed was concealed.
With their knuckles they tapped all over the floor, but the sound emitted was exactly the same everywhere.
For a full hour they searched until suddenly the doctor, who had been indefatigable, while running his hand along the floor close to the oak wainscoting quite near the writing-table, made a discovery which instantly brought his companions upon their knees at his side.
“Look!” he cried. “See! There is a little piece of a different wood let in here—round like a large wooden stud! I wonder what it is?” He pressed it with his fingers, but to no avail. Therefore he took out his pocket-knife and with the end pressed down hard, throwing all his weight upon his hand. “It gives!” he cried excitedly. “There’s some spring behind it! You are stronger,” he exclaimed, turning to the younger man. “Try. Push down, so!”